Fabrication and characterization of small-diameter vascular prostheses

Area of Science:

• Biomaterials Science
• Polymer Engineering
• Vascular Surgery

Background:

• Development of synthetic vascular grafts is crucial for treating cardiovascular diseases.
• Existing methods often struggle to replicate the complex mechanical properties and porous structure of native arteries.
• Polyurethanes offer promising biocompatibility and tunable mechanical characteristics for vascular graft applications.

Purpose of the Study:

• To describe a novel laboratory fabrication process for polyurethane vascular grafts.
• To demonstrate control over graft dimensions, porosity, and mechanical properties.
• To evaluate the structural and mechanical characteristics of the fabricated grafts.

Main Methods:

• Utilized a spray application technique involving a polymer solution and nitrogen gas bubbles onto a mandrel.
• Employed Tecoflex (a polyurethane) and tested variations in fabrication parameters (mandrel RPM, nozzle speed, flow rates).
• Evaluated wall structure via scanning electron microscopy and measured compliance, kink resistance, and suture retention capacity.

Main Results:

• Successfully fabricated polyurethane vascular grafts with controlled inner diameters (3-6 mm) and wall thicknesses (0.5-1.2 mm).
• Achieved tunable wall porosity (30-70%) and bulk pore sizes (10-250 microns).
• Fabricated grafts exhibited compliance values comparable to canine carotid and femoral arteries.

Conclusions:

• The described spray fabrication method offers precise control over polyurethane vascular graft properties.
• This technique enables the production of vascular grafts with mechanical characteristics suitable for arterial reconstruction.
• The developed process holds potential for creating patient-specific vascular grafts.